A 41-year-old elephant named Patience charged and killed a Springfield, Missouri, zookeeper who had come to feed her Friday.

John Phillip Bradford, 62, died in the elephant enclosure at Dickerson Park Zoo, according to Springfield Police Department spokeswoman Lisa Cox. He was the manager of elephants, and had worked at the zoo for 30 years, according to a zoo statement.

Bradford was in the enclosure with two other workers when Patience charged him. The other two workers were unharmed, Cox said.

What set off the incident is unclear.

The zoo referred questions to the city.

"This is very sad day for the Zoo family, as well as our community as a whole," zoo director Mike Crocker said in a written statement.

The elephant has been at the zoo since 1990. The zoo hasn't had any previous problems with its elephants, Cox said.

The zoo's elephant matriarch, Connie, died last week, according to the zoo website.